METHOD FOR ACOUSTIC EMISSION INSPECTION OF COMPOSITE MATERIALS Russian patent published in 2012 - IPC G01N29/14 

FIELD: physics.

SUBSTANCE: primary acoustic-emission information is recorded in the frequency band 20…200 kHz; discrete and continuous acoustic emission is classified; acoustic emission activity is averaged and the scalar criterion is calculated; the primary acoustic-emission information is recorded when loading the analysed object, which is a sample cube measuring 20×20×20 mm, wherein loading is carried out at a constant rate of linear deformation of 5 mcm/s and stopped after time 1.1 t_dc, where t_dc is the time at which recording of the continuous acoustic emission starts; classification of discrete and continuous acoustic emission is carried out by a control program, after which acoustic emission activity is averaged on time from 0 to 0.8t_dc and from 0.8t_dC to t_dc; the scalar criterion is calculated as the product of four and the ratio of the second average to the first; the hazard level of defects of the material is determined by comparing the obtained dimensionless scalar criterion with 1, wherein defects are classified as hazardous if the scalar criterion is less than 1.

EFFECT: method for acoustic emission inspection which employs scalar criteria which are in close correlation with physical and mechanical characteristics of composite materials, values of said criteria enabling to predict the hazard level of defects of the composite material.